Electric heating device



V' 1,613,770 Jan. 11, 1927. L' REICHOLD ELECTRIC HEATING DEVICE FiledAugufift 13J 1925 Patented' Jan. 1l, 1927.

UNITED STATES PATENT OFFICE.

LUDWIG REICHOLD, OF WINSTED, CONNECTICUT, ASSIGNOR TO THE FITZGERALDMANUFACTURING COMPANY, 0F WINSTED, CONNECTICUT, A CORPORATION 0FCONNECTICUT.

ELECTRIC HEATING DEVICE.

applicati@ mea august 1s, 192s. sum m. 49,990.

This invention relates to improvements in electric heatinedevices, andmore particularly to'such p ates of the hot plate type yfor domesticuse. l

It has heretofore been sought to construct electric heating deviceswhich may have the heating element brought into close proximity to thesurface to be heated, and in which the resistance wires are protectedand insulated in a satisfactory manner. The great difficulty of the'previous constructions has been the fact that the heating element wireswere not brought into sufliciently close proximity with theplate toy bcheated, but were held at a distance therefrom, and in par ticular weresubject to physical deterioration by abrasion. Furthermore, in suchdevices it was dilicult to maintain the proper plane relation of theheating element wires with regard to the plate to be heated.

According to the present invention. a very simple and cheaplyconstructed assembly is provided which may be easily assembled anddismounted at need, and yet which presents the heating element wires inclose and positive relation with regard to the plate.

One form of execution of such a' structure is shown on the accompanyingdrawings, in which:

Fig. lfis an elevation of a wafile `iron employingheating elementsaccording to the present invention.-

Fig. 2 is a longitudinal section of the device substantially on line 2-2of Fig. 3, but showing the other parts in position. g'

Fig. 3 is a 'plan of the base plate, with the heating element wire inposition thereon.

This electric heating device has the hot plate section proper withwaflle iron studs thereon atone face, and on the other face a stud 2with a threaded bolt 3 extending there from, the stud heilig arrangedsubstantially at the center of the plate vand projecting at right anglestherefrom.

A disk of mica 4 has a central aperture which closely fits the stud 2,and is received tightly against the surface of the plate 1. This diskserves bothv as electrical and mechanical'protection for the heatingelement.

The heating element assembly has the base plate 5 of relatively thickmetal. AAIt is of substantially circular form, with a central aperture 6therein to adapt it to be placed over and around the vstud 2. Aflattened Gil and are held spaced therefrom by smaller disks 12 ofsimilar material. The preferred method of mounting thesedouble washeras- .semblies is by providing a small hole in the plate 5 at the pointWhere they are to be located; a hollow rivet 11a is then passed throughthe plate 5, the asbestos sheet 10, and the disks 11 and 12, andclinched in posit'on` thus holding the members firmly and ixedlyassembled to form a unitary and rigid Whole.

The terminal bolts 13 and 14 for the heating elementwires are mountedupon the sheet of mica 15, and are separated from the plate 5 by aseries of mica washers 16 which are received in two holes 17 formed inthe plate 5, as may be seen from Fig. 2. These mica washers aresubstantially the same diameter of the holes and when the bolts aredrawn tight they, by their natural irregularity of outline in the usualprocess of manufacture, are held in frictional and overlapping relationwith regard to each other and to the plate, so that the terminal boltsare fixed in position.- In addition to this method of holding theterminal bolts 13 and 14 in place, the mica sheet- 15 projects under theasbestos sheet 10, and is held thereby as well as by the rigidity of theheating element wire itself. n practice it has been found that a veryrigid assembly 1 vhen this plate 5 with the asbestos sheet wir 7 has acentral hole 26 to enable it to fit over and around the threaded bolt 3.A nut 27 is employed to force the ldome into contact with the plate 5,as shown in Fig. 1. It will bev noted that the edge 28 of thisdomeshaped cup 25 engages the plate intermediate the central aperture 6,andthe outer edge of the same.

This device has been shown andv described as being applied toa wafleiron, but it will be understood that it is of far wider application. Inthe particular forni illustrated in Fig. 2 the rear side of the elementis shown as covered and protected by a cap 30 which iits the rebatededge 31 of the plate l, and is held in fixed relation to the otherelements by a nut 32.0n the threaded bolt 3. The plate may have` thehinging lug 34 formed integrally therewith; so that two such eley mentsmay be assembled, as shown in Fig.

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1, and mounted uponv a suitable standard 35 with base 36. The lowerelement A is fastened to the standard 35, while the upper element ishinged to the lower at C and has the lifting handle D for easy and safeoperation.

Obviously, modifications smay be made from the particular embodimentrepresented within the scope of the appended claims.

I claim:

1. In an electric heating device, a heating element assembly consistingof a rigid metal base plate, an insulating sheet upon said base plate,insulating spacing and holding washers on said insulating sheet, metalrivets passing through said late, said sheet, and said washers to fixedy connect the same, terminal bolts secured to and insulated from saidbase plate, and a heating element passing from one terminal bolt toanother in zig zag manner around said washers and held by said bolts andwashers in iixed relation to said b ase plate.

2. In an electric heating device, a heating element assembly having abase plate with apertures therein, an insulating sheet on one side ofsaid base plate, a terminal boltpassing through said sheet and one ofthe apertures, and mica washers substantially of the size of theaperture and disposed about said bolt and in said aperture and extendingbeyond the'same, whereby said bolt upon being drawlitight clamps saidwashers into locking engagement with ythe said base plate and preventsmovement of said bolt with regard to said plate.

3. In an elect-.ric heating device, a heating plate, a clan'iping boltextending from said heating plate, a mica sheet loosely locate-d uponsaid plate and around said bolt; a heating element assembly consistingof a base plate, an insulating sheet on said plate, spacing and holdingwashers on said sheet, rivets passing through said plate, Said sheet andsaid washers to fixedly connect the same, an insulating terminal sheeton said plate, terminal bolts mounted on said terminal sheet, and aheating element` passing from'one terminal bolt to another in zigzagmanner around said washers; a

Aspherical dome-shaped cup having anl aperture for said clamping boltand engaging said base plate intermediate the center and the edge, a nut.on said bolt to clamp said heating element` assembly into close andfixed relation with said heating plate, and a protec'tiner cap inclosingthe heating element assembly.

In testimony whereof, I aiix my signature.

5- LUDWIG REICHOLD.

